Though single-site polymerization catalysts for polyolefin polymerization are well known, there is still a desire for higher activity catalysts capable of operating at high temperatures, and capable of producing crystalline polymers with specific melting points and degrees of crystallinity. There is also a need to understand how to tailor such catalysts such that the polymers produced from these catalysts can be fine-tuned to meet a variety of commercial needs. It would be desirable to utilize the same class of compounds within a given class of catalyst compounds that have similar reactor behavior so that different products can be produced without major disruption in the overall commercial production of polymer.
WO 2007/130306 and WO 2007/130242 disclose transition metal imidazoldiyl olefin polymerization catalysts that are distinct from the present invention. U.S. Pat. No. 6,953,764 discloses pyridyl amide catalysts for olefin polymerization that are distinct from the present invention. Pyridyldiamide catalysts have been described in U.S. Pat. No. 7,973,116; US 2011/0224391; US 2011/0301310; and US 2012/0071616. These pyridyldiamide catalysts are useful in making polyolefins.
The inventors here have found a class of pyridyldiamide catalyst compounds (or “components”) whose structure can be varied to adjust the properties of the resulting polyolefin, especially polypropylene and polyethylene.